M. Odonnell et al., SYNTHETIC PHASED-ARRAYS FOR INTRALUMINAL IMAGING OF CORONARY-ARTERIES, IEEE transactions on ultrasonics, ferroelectrics, and frequency control, 44(3), 1997, pp. 714-721
A 64-element, high efficiency, ceramic piezoelectric array transducer
operating at 20 MHz has been constructed for ultrasonic intraluminal i
maging. The array is mounted on the surface of a 1,2 mm diameter cathe
ter appropriate for coronary artery applications. Integrated into the
catheter tip is a custom analog chip set permitting complete data capt
ure from the array. That is, on each firing any combination of array e
lements can be selected independently as transmitter or receiver. Usin
g data acquired in this way, a complete phased array aperture (i,e., i
ndependent transmit and receive apertures) can be synthesized. Reconst
ruction hardware based an a custom application specific integrated cir
cuit (ASIC) has been designed and built to produce real-time images. B
eam forming coefficients are derived using an optimal filtering approa
ch accounting for the circular geometry of the array. Simulated and me
asured beam patterns for this system are compared. In addition, images
of coronary anatomy acquired with the real-time system are displayed
demonstrating the marked image quality improvement compared to previou
s synthetic aperture intraluminal systems.